At present, in the state of the art, a miniature bulb lighting device for a motor vehicle is known that is particularly used for lighting a glove box, a rear number plate, or as a roof light, a door light, or a courtesy light, the device including a cylindrical miniature or "lillyput" bulb and a bulb support which is fixed to a base which is in turn mounted on the vehicle. The support has two essentially flat and rectangular lamp-supporting elements carrying metal branches for making electrical connections with and for holding the bulb. These bulb support elements are engaged essentially parallel to the plane of the base in fixing grooves provided on the base. To secure said elements in said grooves, the portions of the base that form the walls of said grooves are heated locally so as to cause said walls to melt and partially overlie the support elements. Thus, when the lighting device is installed, the miniature bulb is suspended from the base, being held by said support elements which are themselves held in place by means of solidified melt tongues that extend essentially perpendicular to the direction of the force exerted on said support elements, in particular when removing the bulb.
That lighting device suffers from several drawbacks.
Assembling such a device is complex because of the operation in which the support elements are secured to the base, which operation is not easy to perform. It is necessary to heat the base at the walls of each of the grooves in order to melt the walls onto the support elements, with such heating being capable of causing other elements of the device to be subjected to plastic deformation, e.g. the support elements themselves. In addition, when the base is constituted by a transparent material so as to constitute a window through which light leaves said device, the support-supporting portions after melting, and the supports themselves, form shadow zones of large extent that tend to reduce the lighting efficiency of such a device.
In order to mitigate the last-mentioned drawback, the automatic response of the person skilled in the art is to reduce the extent of the support elements and/or of the melted securing tongues on the base, without completely re-thinking the fastening means used that consist in holding said support elements in place by means of tongues that extend perpendicularly to the force exerted by the bulb on said supports, given that, a priori, the strongest fastening is provided by means extending perpendicularly to the force exerted.